Staring problem??
 

I have an 1990 454 Magnum.

When starting I get the classic "click click"

New battery, no luck.

New cables, no luck.

Rebuilt the starter with new solenoid, no luck.

What's left??

Any suggestions?

The only thing I can think of is the ignition switch.

P.S. Also, once I get it started it "usually" starts instantly

Short in the wire going from the ignition switch to the solenoid or its the ignition switch. Heck, you've replaced everything else.

starting problem
 

starter relay?

It most likley the Slave Solenoid for the starter. Not the one on the starter. If that is not it, check your ground connections.

What he said.
The slave solenoid is a common problem on Mercs.
The longer the boat sits without use the worse it can get, especially in humid conditions.

The solenoid is a "self cleaning" design so the more you use it the better it gets, usually clicking it a few times will clean it off so it will work fine, until you park the boat again for a week or 2...

They are inexpensive so just replace it...

Could still be ignition switch or kill switch or like said before solenoid.
Easy way is to get a check light and have somebody crank it and check at the different locations for + power. Start at the starter. This way you can see if your getting power to the back of the boat.

You are getting power to it, just not enough. Check all connections real good esp. the GROUNDS....

I missed the part its clicking. There is power to the starter. Like said before check Connections.

The slave solenoid makes a clicking sound too, even if it isn't working. Most likely the slave solenoid and is certainly the first spot to look based on what you have done already. Short across the big poles with a screwdriver. That should wake er up.

Also, since you said that "Also, once I get it started it "usually" starts instantly" is another indication of a bad slave solenoid.

Really easy to test it and then replace it.

Don't go to the dash until you have ruled out the slave solenoid.

Power to the starter motor is only one piece of the puzzle. Power to the starter solenoid comes through the slave solenoid from the + terminal on the starter motor, the same terminal the battery is hooked to.

Where is the slave solenoid located?

Is that the same as the slave solenoid?

The starter was rebuilt with new solenoid, and bench tested in front of me (it worked before I rebuilt it, but since it was out, didn't want to take any chance)

Not sure if this matters, but it is the smaller lighter high performance starter. When it works, works fantastic!

Thanks for the clarification, didn't really know how that works, and I'm not near the boat to look at it right now.

a little on the extreme side but we had this happen to a 454 mag and the risers were leaking and there was water in the cylinders. not for nothing but pop out a spark plug and check. good luck.

mercruiserparts.com shows the 454 mag slave solenoid mounted on the bracket that the ignition module and the main 50 amp circuit breaker is mounted(looks like the bracket attaches to one of the cylinder heads. Here is a pic, it is not the same as the starter solenoid, the slave solenoid provides power to actuate the starter solenoid and then the starter motor.

Short across the two big poles on the top of the solenoid with a screw driver or a big jumper wire and the motor should start turning over.

Funny you mention that, never heard of that before.

Similar thing, this summer was trying to help out a guy who could start one engine is his cat. Tried another battery, just click and nothing.

He called a buddy who told him to take a plug out, and gas poured out. took out all the plugs and gas just poured out, and looked like the float got stuck and was just poring fuel into the engine.

Didn't go anywhere that day!

Thanks, and I appreciate the picture, makes things MUCH easier to find and understand

I had one of those fail on my gibson, crusader big blocks, looks the same....wonder why they are even used ?? wonder if you just by pass them ?? the starters used std gm solinoids ?? just a thought...Rob

I believe that the reason slave solenoids are used is to avoid running long wires to the dash to actuate the starter solenoid directly from the ignition switch. The wires are already 10 gauge so to run to the dash and back would take much bigger. Plus corrosion in the wiring and terminals would reduce the current flow to the starter solenoid. Same reason people install electric hatch lift solenoids. Mine got really slow so I hooked up a solenoid with a wire directly to the battery and now the hatch zips up and down.

BUT, those slave solenoids are a pain. I carry an extra and of course there's always the jumper wire/screwdriver.

Boat is back in the water, and I have replaced the slave solonoid, and it worked...

But the next week, same thing, turn the key 10-20 times click click click.... and once the starter kicks in, turns over great.

If the ignition is faulty, I guess I could jump a cable direct to the slave solonoid to see if that works??

Thanks again for the help.